From 555b3652dcb41b67cbdee50713230f5be459e144 Mon Sep 17 00:00:00 2001
From: Dan Kinsley <dan@joincivil.com>
Date: Tue, 12 Feb 2019 16:23:10 -0700
Subject: [PATCH] accounts/abi/bind/backends: add TransactionByHash to
 SimulatedBackend (#19026)

---
 accounts/abi/bind/backends/simulated.go      | 19 ++++++
 accounts/abi/bind/backends/simulated_test.go | 66 ++++++++++++++++++++
 2 files changed, 85 insertions(+)
 create mode 100644 accounts/abi/bind/backends/simulated_test.go

diff --git a/accounts/abi/bind/backends/simulated.go b/accounts/abi/bind/backends/simulated.go
index 6f46fc1495ab..400227c3a8cb 100644
--- a/accounts/abi/bind/backends/simulated.go
+++ b/accounts/abi/bind/backends/simulated.go
@@ -164,6 +164,25 @@ func (b *SimulatedBackend) TransactionReceipt(ctx context.Context, txHash common
 	return receipt, nil
 }
 
+// TransactionByHash checks the pool of pending transactions in addition to the
+// blockchain. The isPending return value indicates whether the transaction has been
+// mined yet. Note that the transaction may not be part of the canonical chain even if
+// it's not pending.
+func (b *SimulatedBackend) TransactionByHash(ctx context.Context, txHash common.Hash) (tx *types.Transaction, isPending bool, err error) {
+
+	tx = b.pendingBlock.Transaction(txHash)
+	if tx != nil {
+		return tx, true, nil
+	}
+
+	tx, _, _, _ = rawdb.ReadTransaction(b.database, txHash)
+	if tx != nil {
+		return tx, false, nil
+	}
+
+	return nil, false, ethereum.NotFound
+}
+
 // PendingCodeAt returns the code associated with an account in the pending state.
 func (b *SimulatedBackend) PendingCodeAt(ctx context.Context, contract common.Address) ([]byte, error) {
 	b.mu.Lock()
diff --git a/accounts/abi/bind/backends/simulated_test.go b/accounts/abi/bind/backends/simulated_test.go
new file mode 100644
index 000000000000..ac6e9e228a3b
--- /dev/null
+++ b/accounts/abi/bind/backends/simulated_test.go
@@ -0,0 +1,66 @@
+package backends_test
+
+import (
+	"context"
+	"math/big"
+	"testing"
+
+	ethereum "github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/accounts/abi/bind"
+	"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto"
+)
+
+func TestSimulatedBackend(t *testing.T) {
+	var gasLimit uint64 = 8000029
+	key, _ := crypto.GenerateKey() // nolint: gosec
+	auth := bind.NewKeyedTransactor(key)
+	genAlloc := make(core.GenesisAlloc)
+	genAlloc[auth.From] = core.GenesisAccount{Balance: big.NewInt(9223372036854775807)}
+
+	sim := backends.NewSimulatedBackend(genAlloc, gasLimit)
+
+	// should return an error if the tx is not found
+	txHash := common.HexToHash("2")
+	_, isPending, err := sim.TransactionByHash(context.Background(), txHash)
+
+	if isPending {
+		t.Fatal("transaction should not be pending")
+	}
+	if err != ethereum.NotFound {
+		t.Fatalf("err should be `ethereum.NotFound` but received %v", err)
+	}
+
+	// generate a transaction and confirm you can retrieve it
+	code := `6060604052600a8060106000396000f360606040526008565b00`
+	var gas uint64 = 3000000
+	tx := types.NewContractCreation(0, big.NewInt(0), gas, big.NewInt(1), common.FromHex(code))
+	tx, _ = types.SignTx(tx, types.HomesteadSigner{}, key)
+
+	err = sim.SendTransaction(context.Background(), tx)
+	if err != nil {
+		t.Fatal("error sending transaction")
+	}
+
+	txHash = tx.Hash()
+	_, isPending, err = sim.TransactionByHash(context.Background(), txHash)
+	if err != nil {
+		t.Fatalf("error getting transaction with hash: %v", txHash.String())
+	}
+	if !isPending {
+		t.Fatal("transaction should have pending status")
+	}
+
+	sim.Commit()
+	tx, isPending, err = sim.TransactionByHash(context.Background(), txHash)
+	if err != nil {
+		t.Fatalf("error getting transaction with hash: %v", txHash.String())
+	}
+	if isPending {
+		t.Fatal("transaction should not have pending status")
+	}
+
+}